Micro paddle wheel pump for precise pumping, mixing, dispensing, and valving of blood and reagents

ABSTRACT

An apparatus and method for making a microscopic paddle wheel coupled inductively by an external electromagnet and used for valving and active pumping so that the actual pumping mechanism is completely isolated from the electromagnetic driver. The paddle wheel is inexpensive to manufacture and disposable. A cartridge having a network of conduits and reservoirs contains several of such paddle wheels to transport blood and reagents. A point-of-care device houses the electromagnetic driving mechanism and is reused with successive cartridges since the paddle wheels are contained by the cartridge and do not contaminate the driving mechanism.

This application is a divisional of U.S. Pat. No. 6,607,362 (Ser. No.09/976,991) filed on Oct. 11, 2001.

FIELD OF THE INVENTION

The present invention is related to Micro Electro Mechanical Systems(“MEMS”). This field includes micro-fluidics, micro-pumping,micro-valves, precise fluid dispensing, micro-molding, andmicro-magnetic actuators. More particularly, the invention relates todevices and methods for microscopic pumping, mixing, dispensing, andvalving of blood and reagents.

BACKGROUND OF THE INVENTION

Micro-pumping for transporting small volumes of fluids is made possibleby micro-pumps which use piezoelectric, surface wave, thermal, fluidicor static electric actuation to move diaphragms, membranes, flappers,wheels, or actual fluids. This has been discussed in the literature.

The term “micro” refers to objects of small scale having dimensions onthe microscopic level. Such a microscopic level includes orders ofmagnitude of 1×10⁻³ meters to about 1×10⁻⁷ meters, where 1×10⁻⁶ metersis commonly referred to as a micron. Such orders of magnitude correspondto dimensions such as volume and mass.

Blood flow sensors have been constructed out of polysilicon rotors. Thegoal of such devices is to position them in blood vessels and measurethe flow that might change as a result of an occlusion. Rapoport, S. D.,et al., Fabrication and testing of a microdynamic rotor for blood flowmeasurements, Journal of Micromechanical Microengineering 1, (1991), pp.60–65. This article is incorporated by reference herein. A rotor 300microns in diameter was machined out of polysilicon. A two micron thickhub was attached to the center of the rotor to allow the rotor to rotatein a seven micron gap. The rate of rotation of the rotor is measuredusing a microscopic permanent magnet to modulate the resistance of apermalloy placed near the rotor. The change in resistivity provides anelectrical signal, the frequency of which is proportional to therotation rate, and hence the velocity.

The durability and robustness of micro rotors has been improved byadding polysilicon bearings to the point of rotation to overcome thelack of ball bearings and lubricants which exist in conventional sizedrotors. Tavrow, Lee S., Operational characteristics of microfabricatedelectric motors, Sensors and Actuators 35 (1992), pp. 33–44. Thisarticle is incorporated by reference herein. The life of the rotor isincreased significantly with the addition of such bearings.

In conventional magnetic actuators, most of the magnetic energy isstored in the gap due to the large reluctance of the magnetic core.However, in magnetic micro-actuators the fabrication limitations on theachievable cross-sectional area of the magnetic core as well as thefinite core permeability increase the core reluctance to the point thatthis assumption may no longer be valid. Nami, Z. et al., An energy-baseddesign criterion for magnetic microactuators, Journal of MicromechanicalMicroengineering 6, (1996), pp. 337–344. This article is incorporated byreference herein. The reluctance problem is overcome by sizing the gapbetween core and coils according to the actuator requirements so thatthe reluctance of the gap and the reluctance of the core are equal.

In order to produce a magnetic force (or actuation) at a specificlocation, magnetic micro-actuators should have an inductive component togenerate magnetic flux to the point where actuation takes place. Ahn,Chong H., et al., A fully integrated surface micromachined magneticmicroactuator with multi-meander magnetic core, Journal ofMicroelectromechanical Systems, Vol. 2, No. 1, March 1993. This articleis incorporated by reference herein. Directed pin-point actuation hasbeen achieved using solenoid coils and micro-machined nickel-iron coreson the order of 25 microns wide and requiring a current of 800 mA foractuation.

Magnetic micro-platforms, on the order of one mm², powered by localelectromagnets, require a current of 182 mA for actuation due toimprovements in the local magnetic source by reducing reluctance andusing thinner micro-platforms which reduce the length theelectromagnetic field must travel through air. Chang, Carl, et al.,Magnetically actuated microplatform scanners for intravascularultrasound imaging, MEMS-Vol. 2 Micro-Electro-Mechanical Systems(MEMS)-2000, ASME 2000. This article is incorporated by referenceherein.

Piezoelectric micro motors have been designed with diameters of 2–5 mmwhich require four volts at 90 kHz to generate 100–300 rpm. Flynn, AnitaM., Piezoelectric Ultrasonic Micromotors, Massachusetts Institute ofTechnology, PhD dissertation June 1995. This paper is incorporated byreference herein. These devices are ultrasonic and provide the advantageof a holding torque when the sound wave is not traveling between thestationary and rotating aspects of the motor.

Methods for fabricating such devices using processes similar tointegrated circuit manufacturing have been suggested. Zettler, Thomas,Integrated circuit fabrication compatible three-mask tungsten processfor micromotor and gears, Sensors and Actuators 44, (1994), pp. 159–163.This reference in incorporated by reference herein.

The problem with existing microdevices is that several units arenecessary to pump, valve, mix, and meter blood and reagents. This isprohibitive where space is limited, such as in a hand-held point-of-caredevice for analyzing blood samples. For such an application compactdesign and mass manufacturing are necessary due to the size andbiohazard constraints. Henceforth, the term “biological fluid” will beused to mean bodily fluid samples, such as blood, and/or other reagentchemicals; such reagents preferably support a variety of analyticalmethods including electrochemical, chemiluminescence, optical,electrical, mechanical, and others, for determination of blood pH, pO₂,pCO₂, Na⁺, Ca⁺⁺, K⁺, hematocrit, glucose, and coagulation and hemoglobinfactors.

It is accordingly a primary object of the invention to integratevalving, pumping, mixing, and metering of biological fluid byincorporating the valve and pump mechanisms as an integral micro-pumpingunit that can be manufactured at low cost such that the user can discarda device using such micro-pumps after a single use.

This is achieved by designing the micro-pump so that it is easilyfabricated with existing MEMS and plastics technologies. The micro-pumpis assembled within a disposable cartridge that operates in conjunctionwith a point-of-care analytical device. During the fabrication andassembly process of such a cartridge, the micro-pumps may be discretelyfabricated and tested then assembled into the cartridge. Alternatively,the micro-pumps may be assembled within such a cartridge and tested onthe actual cartridge itself once it has been inserted into thepoint-of-care analytical device.

SUMMARY OF THE INVENTION

In accordance with the invention, a microscopic paddle wheel is coupledinductively by an external electromagnet and is used for valving andactive pumping. Such a system takes advantage that the actual pumpingmechanism is completely isolated from the electromagnet driver. Thepaddle wheel is inexpensive to manufacture and disposable. A cartridgemay have a network of conduits and reservoirs containing several suchpaddle wheels to transport biological fluid. A point-of-care devicehousing the electromagnetic driving mechanism is reused with successivecartridges since the paddle wheels are contained by the cartridge and donot contaminate the driving mechanism.

An inductive drive such as an electromagnet and a magnetic coreincorporated within the paddle wheel to actuate the motion may beseparated by either plastic or silicon approximately one millimeterthick and still maintain an inductive coupling with the paddle wheelsuch that the magnetic core spins by rotating the magnetic field. Theelectromagnet may be a micro-coil which causes the paddle wheel to moveaccording to the alternating field in the micro-coil.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

The accompanying drawing, which is incorporated in and constitutes apart of this specification, illustrates an embodiment of the inventionand, together with the description, serves to explain the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a three-dimensional cut-away drawing of the paddle wheelresting within a conduit housed in a cartridge.

FIG. 2 is a three-dimensional cut-away drawing of the point-of-careanalytic device, and an associated cartridge showing a network ofconduits and reservoirs, according to one or more embodiments of thepresent invention.

DESCRIPTION OF THE EMBODIMENTS

The term “micro pumping device” refers to a pump using momentum transferprinciples on the microscopic scale. A micro pumping device cannotcontain many movable parts since it must be constructed from micromolding techniques.

Micro-molded devices are made and molded using LIGA (German acronym forLithographie, Galvanoformung, Abformung). LIGA processes uselithography, electroplating, and molding to produce microstructures.These processes are capable of creating finely defined microstructuresof up to 1000 μm high. The paddle wheel does not require such finedefinition and may have microstructures up to several millimeters high.The paddle wheel may be fabricated by LIGA or other micro-moldingtechniques separate from the cartridge which houses the paddle wheel.The paddle wheels are small enough to be integrated upon final assemblyof the cartridge by being dropped into place in the cartridge moldedhousing.

Various micro-machining technologies have been developed for MEMSdevices and structures. Micro-riveting has been developed tomechanically join two plates together while avoiding the demandingprocesses of bonding. Micro-channeling to form conduits, a basicbuilding block for microfluidic devices, uses a simple, room-temperatureprocedure, which requires only one-mask step and no bonding. Many of thetechniques used in integrated chip design have been applied to MEMS,such as detailed lithography. Process technologies include focused ionbeam (FIB) micro-manufacturing to create cutting tools for use in makingmicrostructure molds and deep x-ray lithography (DXRL) masks that areused to create micro-mechanical structures and systems.

The paddle wheels may be molded with a small solid magnetic core such asiron embedded in the center to serve as the actuator which isinductively coupled by the electromagnet. The paddle wheel is moldedprecisely so that the magnetic core is centered vertically and radiallywithin the paddle wheel. The paddle wheel is positioned precisely sothat the alignment of the magnetic core allows for accurate movement bythe electromagnet. Precise micro-droplet dispensing is used tomicro-pick and place the paddle wheel into micro-pump conduits thatcontain paddle wheel chambers to house the paddle wheels recessed in theconduits to facilitate cartridge assembly. Many paddle wheels may beplaced within the conduits of the cartridge.

Micro-droplet dispensing for positioning the micro paddle wheelcomprises using micro-manipulation with micro-grippers powered bymicro-motors. The micro-grippers, which resemble forceps, may beconfigured such that when closed together the grippers form a cavitysimilar to the exterior shape of the micro paddle wheel. The grippersurface may have variable roughness depending of the hardness of thematerial used to construct the micro paddle wheel to avoid damaging themicro paddles during gripping and dispensing.

To facilitate micro-assembly, the paddle wheel can be positioned intothe paddle wheel chamber with the aid of a member of the shaped to filla portion of the paddle wheel chamber and couple to the paddle wheel.The member can be constructed of a similar material as the paddle wheelto avoid fluid effects between the paddle wheel and the member. Even ifconstructed of a different material, the member should exhibit the samehydrophobic surface properties as the paddle wheel.

The point-of-care device may contain many electromagnets in the form ofsmall coils distributed throughout the surface of the device thatinteract with the cartridge. The electromagnets do not require asignificant amount of current and power to drive the paddle wheels andtransport biological fluid throughout the cartridge. The paddle wheelsalso act as valves to isolate the biological fluid prior and afterpumping to control reaction time and isolate analytical reactions. Thisis achieved by taking advantage of the capillary flow properties offluids when the paddle wheel is inactive.

The paddle wheel includes a hydrophobic surface which repels thebiological fluid. The paddle wheel is made of a hydrophobic polymer suchthat its surface has such hydrophobic properties. In motion, the paddlewheel does not adhere to the biological fluid. When inactive, the paddlewheel repels the biological fluid to create a barrier and valve theconduit. The conduit includes a hydrophilic interior wall to attract thebiological fluids as they pass by the paddle wheel. The conduit wall ismade hydrophilic by using plasma or corona surface treatment.

While polymers, particularly materials like polypropylene andpolyethylene, offer many beneficial properties for MEMS, theirhydrophobic properties (poor wettability) creates limitations when itcomes to designing conduits out of these materials. Ideally, the surfaceenergy of the polymer conduit should be about 10 dynes/cm greater thanthe surface tension of the biological fluid such that the fluid “wets”the surface.

Corona surface treatment uses an electric current to create an ozonegenerating spark which increases the polymer's surface energy. The ozonewithin the corona reacts with the polymer surface to raise the energylevel. The corona surface treatment process includes passing the polymerthrough a highly charged electrical field which bombards the surface inthe presence of oxygen (air). This microsurface modification throughoxidation makes the surface hydrophilic, thus increasing itswettability.

Plasma surface treatment, in general, changes the wetting properties ofpolymers. Plasma treatment cures this problem by treating the polymerwith a partially ionized gas or mixture of gases. The ionized particlesare accelerated in an electrical field such that their energy ofexcitation is comparable or exceeds the bond energy of the polymersurface. When the ionized particles strikes the solid polymer surface itejects an electron (secondary electron emission) or atom (sputtering),traps the ionized particles (ion implantation, electron trapping),becomes structurally rearranged at points or throughout the surface,chemically reacts with the ionized particles, or a combination of theabove. The plasma may also comprise UV radiation that also that aids inthe surface treatment process.

The parameters of the plasma treatment, including but not limited tofrequency, intensity, pressure, and mixture of gases, vary depending onthe polymer and its surface properties and the degree of hydrophilicconversion desired. Plasma treatment is usually fast and affects about10 nanometers of the uppermost polymer surface layer. The increase ofwettability of the film is attributed to a combination of factorsincluding UV radiation and oxidation of functional groups to alter theoxygen to carbon atomic ratio on the polymer surface.

The paddle wheels also mix components of the biological fluid passingthough the paddle wheel simultaneously by using the torsion forces ofthe paddles to create turbulence and mix the biological fluid passingthrough the micro-pump. The torsion force, however, does not exceed thelevel that would lyse or puncture blood cells.

The number of turns of the paddle wheel may serve as a precision meterof how much biological fluid is pumped. The precise molding of thepaddle wheel allows for specific volumes of biological fluid to bemetered between each pair of paddles. The accurate control by theelectromagnet allows the rotation of the paddle wheel to be manipulatedso that a known amount or metered volume of biological fluid is allowedto pass through the micro-pump. By coupling the micro-pump in such anexact manner the point-of-care analytical device uses an algorithm toestablish precise flow rates and dispense precise biological fluidratios such as between blood and reagent. The device may control themixing ratio of blood and reagent by dispensing blood and reagents atdifferent flow rates into a common mixing reservoir. Such control allowsmore accurate aliquots for the analytical assays carried out by thedevice.

Reference will now be made in detail to the present embodiment of theinvention, an example of which is illustrated in the accompanyingdrawing. Wherever possible, the same reference numbers will be usedthroughout the drawing to refer to the same or like parts.

Biological fluids are attracted to hydrophilic surfaces and repulsed byhydrophobic surfaces. FIG. 1 shows the paddle wheel (10) with embeddedmagnetic core (12). The paddle wheel (10) comprises of several paddles(14). The paddles (14) are fabricated from polymer materials, such aspolyvinyl chloride, which are hydrophobic. The biological fluid (16)will be repulsed by the surface of the paddles (14). The conduit (18)has an inside surface treated with corona or plasma surface treatmentswhich render the surface hydrophilic. The biological fluid (16) will beattracted to the inside surface of conduit (18). To reduce head spaceand facilitate manufacturing a D-shaped member (20) fabricated fromhydrophobic polymer material may be used to fill the area above andbelow the paddle wheel (10).

The paddle wheel (10) has two protrusions along its rotational axiswhich act as pivot points for the rotation of the paddle wheel (10)leaving the paddles (14) free to rotate. The diameter (D) of the paddlewheel (10), as measured by the width of the opposing paddles (14), isgreater than the width (W) of the conduit (18). These protrusions fitwithin a cylindrical cavity within each of the D-shaped member (20). Thepaddle wheel (10) fits into the paddle wheel chamber (22) recessed inconduit (18). The paddle wheel chamber (22) adds sufficient width to thewidth (W) of the conduit (18) to accommodate the diameter (D) of paddlewheel (10). The D-shaped member (20) fills the vertical expansion (24)of the conduit (18). There is a second D-shaped member (not shown)filling a second vertical expansion (not shown) above the paddle wheel(10). The member (20) facilitates assembly of a cartridge by insertingthe member (20) in expansion (24) then inserting the protrusion ofpaddle wheel (10) into the cylindrical cavity of member (20). The member(20) similar to the paddle wheel (10) repulses the biological fluid(16). The combined hydrophobic surface conditions created by both thepaddles (14) and member (20) prevent the biological fluid (16) fromflowing into the overhead regions of the micro-pump to reduce the totalfluid volume requirements necessary for operating the pump. The member(20) acts as a hydrophobic member to facilitate assembly and reduceoverhead flow.

When the paddle wheel (10) is stationary, the hydrophilic interiorsurface of the conduit (18) and the hydrophobic surface of paddles (14)retain the biological fluid (16) on one side of the paddle wheel (10)allowing the micro-pump to act as a valve. When the paddle wheel (10) isin rotational motion, as a result of changing the field of theelectromagnet (not shown), the hydrophobic surface of the paddles (14)will sweep the biological fluid (16) from the hydrophilic surface ofconduit (18) upstream of the paddle wheel (10) to the hydrophilicsurface of conduit (18) downstream of the paddle wheel (10).

The scooping area between paddles (14) is preferably sized toaccommodate a predetermined volume of biological fluid (16) moved witheach rotation of the paddle wheel (10). In addition, the paddle wheel(10) may be used to mix the components of the biological fluid (16).

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

FIG. 2 illustrates a representative point-of-care analytic device 36 aswell as a cartridge, such as a disposable cartridge 34, that operates inconjunction with a point-of-care analytical device 36. The disposablecartridge 34 can have a network of conduits 18 and reservoirs 26containing several paddle wheels 10 to transport biological fluid.According to one or more embodiments, the paddle wheels 10 may becoupled inductively to an external electromagnet 42 that can be housedwithin the point-of-care analytic device 36. In some embodiments, theelectromagnetic drive mechanism can be a micro-coil 38 which causes thepaddle wheel 10 to move according to the alternating field in themicro-coil 38.

1. A disposable cartridge that operates in conjunction with apoint-of-care analytical device, said cartridge comprising: a network ofconduits and reservoirs within said cartridge; and at least one micropump fluidly coupled to said network for transporting small volumes ofbiological fluid, said pump comprising: a rotatable portion having amagnetic core and configured to be rotatable by alternating inductivemagnetic fields to urge fluid through said network, wherein saidrotatable portion comprises a microscopic paddle wheel.
 2. Thedisposable cartridge of claim 1 wherein said alternating inductivemagnetic fields provide a torsion force to the rotatable portion thatdoes not exceed the level that would lyse or puncture blood cells. 3.The disposable cartridge of claim 1 wherein a plurality of micro pumpsare placed within the network of the cartridge.
 4. The disposablecartridge of claim 1 wherein said micro pump is fluidically isolatedfrom a source of the alternating inductive magnetic fields.
 5. Thedisposable cartridge of claim 1 wherein the rotatable portion iscontained within the disposable cartridge so that the rotatable portionis isolated from and does not contaminate a source of the alternatinginductive magnetic fields.
 6. The disposable cartridge of claim 1wherein an actual pumping mechanism of the micro pump is completelyisolated from a source of the alternating inductive magnetic fields. 7.The disposable cartridge of claim 1 wherein the paddle wheel inmicro-pump conduits that contain paddle wheel chambers to house thepaddle wheels recessed in the conduits to facilitate cartridge assembly.8. The disposable cartridge of claim 1 wherein the paddle wheel acts asa valve in the network to isolate the biological fluid prior and afterpumping to control reaction time and isolate analytical reactions.
 9. Adisposable cartridge that operates in conjunction with a point-of-careanalytical device, said cartridge comprising: a network of conduits andreservoirs within said cartridge; and at least one micro pump fluidlycoupled to said network for transporting small volumes of biologicalfluid, said pump comprising: a rotatable portion having a magnetic coreand configured to be rotatable by alternating inductive magnetic fieldsto urge fluid through said network, wherein said rotatable portioncomprises a microscopic paddle wheel having a hydrophobic surface. 10.The disposable cartridge of claim 9 wherein said alternating inductivemagnetic fields provide a torsion force to the rotatable portion thatdoes not exceed the level that would lyse or puncture blood cells. 11.The disposable cartridge of claim 9 wherein a plurality of micro pumpsare placed within the network of the cartridge.
 12. The disposablecartridge of claim 9 wherein said micro pump is fluidically isolatedfrom a source of the alternating inductive magnetic fields.
 13. Thedisposable cartridge of claim 9 wherein the rotatable portion iscontained within the disposable cartridge so that the rotatable portionis isolated from and does not contaminate a source of the alternatinginductive magnetic fields.
 14. The disposable cartridge of claim 9wherein an actual pumping mechanism of the micro pump is completelyisolated from a source of the alternating inductive magnetic fields. 15.The disposable cartridge of claim 9 wherein the paddle wheel inmicro-pump conduits that contain paddle wheel chambers to house thepaddle wheels recessed in the conduits to facilitate cartridge assembly.16. The disposable cartridge of claim 9 wherein the paddle wheel acts asa valve in the network to isolate the biological fluid prior and afterpumping to control reaction time and isolate analytical reactions.
 17. Apoint-of-care analytical device, said device comprising: a disposablecartridge; a network of conduits and reservoirs within said cartridge; amicro pump fluidly coupled to said network for transporting smallvolumes of biological fluid, said pump comprising a rotatable portionconfigured to be rotatable by alternating inductive magnetic fields tourge fluid through said network; and an external electromagnet providingsaid alternating inductive magnetic fields for causing the rotatableportion to move to transport small volumes, said electromagnetpositioned external to said disposable cartridge and fluidicallyisolated from said micro pump; wherein said rotatable portion comprisesa microscopic paddle wheel coupled inductively to said externalelectromagnet.
 18. The point-of-care device of claim 17 wherein theelectromagnet is reused with successive disposable cartridges and therotatable portion is contained in the cartridge and does not contaminatethe electromagnet.
 19. The point-of-care device of claim 17 wherein anactual pumping mechanism of the micro pump is completely isolated fromsaid external electromagnet.
 20. The point-of-care device of claim 17wherein the electromagnet comprises a micro-coil which causes the paddlewheel to move according to the alternating field in the micro-coil. 21.The point-of-care device of claim 17 wherein the paddle wheel inmicro-pump conduits that contain paddle wheel chambers to house thepaddle wheels recessed in the conduits to facilitate cartridge assembly.22. The point-of-care device of claim 17 where the paddle wheels act asvalves in the network to isolate the biological fluid prior and afterpumping to control reaction time and isolate analytical reactions. 23.The point-of-care device of claim 17 wherein said alternating inductivemagnetic fields provide a torsion force to the rotatable portion thatdoes not exceed the level that would lyse or puncture blood cells. 24.The point-of-care device of claim 17 wherein a plurality of micro pumpsare placed within the network of the cartridge.
 25. The point-of-caredevice of claim 17 wherein the rotatable portion is contained within thedisposable cartridge so that the rotatable portion is isolated from anddoes not contaminate said external electromagnet.
 26. A point-of-careanalytical device, said device comprising: a disposable cartridge; anetwork of conduits and reservoirs within said cartridge; a micro pumpfluidly coupled to said network for transporting small volumes ofbiological fluid, said pump comprising a rotatable portion configured tobe rotatable by alternating inductive magnetic fields to urge fluidthrough said network; and an external electromagnet providing saidalternating inductive magnetic fields for causing the rotatable portionto move to transport small volumes, said electromagnet positionedexternal of said disposable cartridge and fluidically isolated from saidmicro pump; wherein said rotatable portion comprises a microscopicpaddle wheel coupled inductively to said external electromagnet; andwherein the paddle wheel to actuate the motion may be separated byeither plastic or silicon and still maintain an inductive coupling withthe paddle wheel such that the magnetic core spins by rotating themagnetic field.
 27. The point-of-care device of claim 26 wherein theelectromagnet is reused with successive disposable cartridges, andwherein an actual pumping mechanism of the micro pump is containedwithin the cartridge so that it is completely isolated from and does notcontaminate said external electromagnet.
 28. The point-of-care device ofclaim 26 wherein the electromagnet comprises a micro-coil which causesthe paddle wheel to move according to the alternating field in themicro-coil.
 29. The point-of-care device of claim 26 wherein the paddlewheel in micro-pump conduits that contain paddle wheel chambers to housethe paddle wheels recessed in the conduits to facilitate cartridgeassembly.
 30. The point-of-care device of claim 26 wherein saidalternating inductive magnetic fields provide a torsion force to therotatable portion that does not exceed the level that would lyse orpuncture blood cells.
 31. The point-of-care device of claim 26 wherein aplurality of micro pumps are placed within the network of the cartridge.32. The point-of-care device of claim 26 wherein the paddle wheel actsas a valve in the network to isolate the biological fluid prior andafter pumping to control reaction time and isolate analytical reactions.